[3] Finnish authorities are investigating the incident and suspect that the oil tanker Eagle S, believed to be part of the Russian shadow fleet, had intentionally caused the cable ruptures by dragging its anchor.

[13] On 30 December, an application was filed to the Helsinki District Court [fi], in which the Eagle S's shipping company, Caravella, seeks to overturn the seizure by the Finnish authorities.

[17] Eagle S, registered in the Cook Islands, was not on the list of 79 ships sanctioned by the EU at the time of the incident;[18] it was however believed to be part of the Russian shadow fleet.

[2] According to Sami Rakshit [fi] head of the Finnish Customs, the case is also being investigated for a serious regulatory offense of evasion of sanctions imposed on Russia following its invasion of Ukraine, as the vessel was carrying 35,000 tons of unleaded gasoline.

[26] The police confirmed that the tanker is suspected of having caused the failure and that the incident is being investigated as an act of gross sabotage [fi][27][28] (criminal code fin.

[32] On 29 December, the Helsinki Police Department reported that investigations are continuing, but adverse weather conditions at the anchorage have slowed down operations.

Criminal inspector Sami Paila from the NBI said that "underwater investigations have so far mapped the drag track on the seabed from start to finish.

[38] As of 3 January the Eagle S not only remained under detention by the criminal investigation (a court ruled)[39] and port inspection, but civil litigation brought by Fingrid for the cost of repair of their submarine power cable.

Pekka Toveri, retired general and Member of the European Parliament, called the statements made in the Washington Post "total rubbish".

[44] On January 22, Sweden's SVT reported that most Nordic government branches dismiss the claims by Washington Post, with a Swedish consensus that it is too early to draw a conclusion while investigation proceeds.

Jukka Savolainen, network director of the European Centre of Excellence for Countering Hybrid Threats, claimed that Washington Post spread pro-Russian fake news.

[52] Estonia's president Alar Karis said on X that "repeated damage to Baltic Sea infrastructure signals a systemic threat, not mere accidents.

"[53] Prime minister Kristen Michal said at a news conference that the shadow tankers "are helping Russia to earn funds that will aid Russian hybrid attacks,[54] and Defence Minister Hanno Pevkur announced on public radio that the patrol ship Raju had set sail on Tuesday (24 December) to protect Estlink 1.

[55] Professor of criminal law Sakari Melander [fi] told Helsingin Sanomat, that "here it seems justified to consider the use of coercive measures.

Matti Tolvanen [fi], professor emeritus of criminal and procedural law, said that if the ship is allowed to leave, there is little chance of the matter being taken to court or even investigated.

"I can't say anything for sure, it's a very narrow-profile question, which is hardly the prerogative of the presidential administration," Kremlin spokesman Dmitry Peskov said when asked by a Reuters journalist to comment on the actions of the Finnish authorities.

[63] In late November 2024, Australia and New Zealand had endorsed a joint Call to Action against Russian and North Korean shadow fleet activity.